Experiments are reported on optical ionization of gases produced by 12 ps pulses of focused KrF laser radiation at intensities of 3 X 1017 W/cm2. Simultaneous measurements of Thomson, stimulated Raman and stimulated Brillouin scattering have been used to determine the electron energy distribution and temperature in He and Ne (static and pulsed gas jet targets) at pressures of 10-3 - 1 bar. The electron velocity distribution evolves from a multiphoton ionization spectrum at low pressure to a thermal electron distribution at higher pressure. The ion determined portion of the Thomson scattered spectrum is highly non-thermal for pressures > a few mbar. At high pressure, significant Raman and Brillouin backscattering are observed. The results show that inverse bremsstrahlung absorption dominates heating for p > 10-2 bar except at the highest pressures where SRS may also be important.